Write pole shield having a low saturation magnetization layer

ABSTRACT

A recording head that includes a bearing surface and a write pole having a front surface that forms a portion of the bearing surface. The recording head also includes a side shield for the write pole. The side shield includes a low saturation magnetization cap layer having a front surface that forms a portion of the bearing surface. The side shield also includes a main side shield layer having a saturation magnetization that is higher than a saturation magnetization value of the low saturation magnetization cap layer.

BACKGROUND

Data storage devices use magnetic recording heads to read and/or writedata on magnetic storage media, such as data storage discs. Magneticrecording heads typically include inductive write elements to recorddata on the storage media. An inductive write element or transducer mayinclude a main pole having a pole tip and one or more return poles.Current is supplied to write coils to induce a flux path in the mainpole to record data on one or more magnetic storage layers of the media.

With ever-increasing levels of recording density in disc drives, thewrite element needs to have correspondingly better data-recordingcapabilities and needs to be reliable.

SUMMARY

Embodiments of the disclosure relate to write pole side shields for arecording head that include features that help improve reliabilityand/or performance of the recording head.

In one embodiment, a recording head is provided. The recording headincludes a bearing surface and a write pole having a front surface thatforms a portion of the bearing surface. The recording head also includesa side shield for the write pole. The side shield includes a lowsaturation magnetization cap layer having a front surface that forms aportion of the bearing surface. The side shield also includes a mainside shield layer having a saturation magnetization that is higher thana saturation magnetization value of the low saturation magnetization caplayer.

Other features and benefits that characterize embodiments of thedisclosure will be apparent upon reading the following detaileddescription and review of the associated drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A illustrates an embodiment of a data storage device in whichembodiments of the present application can be used.

FIG. 1B is a schematic illustration of a head including one or moretransducer elements above a magnetic recording medium.

FIG. 2A depicts a bearing surface view of a perpendicular magneticrecording (PMR) transducer in accordance with one embodiment.

FIG. 2B depicts a side view of the PMR transducer of FIG. 2A.

FIG. 2C depicts a bearing surface view of a PMR transducer in accordancewith another embodiment.

FIG. 2D depicts a side view of the PMR transducer of FIG. 2C.

FIG. 3A shows a bearing surface view of a write head that includes a lowsaturation magnetization side shield cap layer in accordance with oneembodiment.

FIG. 3B is an inside view of the write head of FIG. 3A.

FIG. 3C shows a bearing surface view of a write head that includes a lowsaturation magnetization side shield cap layer in accordance withanother embodiment.

FIG. 3D is an inside view of the write head of FIG. 3C.

FIG. 3E shows a bearing surface view of a write head that includes a lowsaturation magnetization side shield cap layer in accordance with yetanother embodiment.

FIG. 4 is a graph of experimental results.

FIG. 5A shows a bearing surface view of a write head that includes aback step feature in accordance with one embodiment.

FIG. 5B is an inside view of the write head of FIG. 5A.

FIG. 5C shows a bearing surface view of a write head that includes aback step feature and a low saturation magnetization side shield caplayer in accordance with one embodiment.

FIG. 5D is an inside view of the write head of FIG. 5C.

FIG. 5E is a top-down view of the write head of FIG. 5C.

FIG. 5F shows a bearing surface view of a write head that includes aback step feature in accordance with another embodiment.

FIG. 5G is an inside view of the write head of FIG. 5F.

FIG. 5H shows a bearing surface view of a write head that includes aback step feature and a low saturation magnetization side shield caplayer in accordance with yet another embodiment.

FIG. 5I is an inside view of the write head of FIG. 5H.

FIG. 5J is a top-down view of the write head of FIG. 5H.

FIG. 6 is another graph of experimental results.

FIG. 7 is a flow diagram of a method embodiment.

FIGS. 8A-8J illustrate process steps for fabricating a write head of thetype shown in FIG. 3A.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

Embodiments of the disclosure relate to write pole side shields for arecording head that include features that help improve reliabilityand/or performance of the recording head. However, prior to providingdetails regarding the different embodiments, a description of anillustrative operating environment is provided below.

FIG. 1A shows an illustrative operating environment in which certainrecording head embodiments as disclosed herein may be incorporated. Theoperating environment shown in FIG. 1A is for illustration purposesonly. Embodiments of the present disclosure are not limited to anyparticular operating environment such as the operating environment shownin FIG. 1A. Embodiments of the present disclosure are illustrativelypracticed within any number of different types of operatingenvironments.

It should be noted that like reference numerals are used in differentfigures for same or similar elements. It should also be understood thatthe terminology used herein is for the purpose of describingembodiments, and the terminology is not intended to be limiting. Unlessindicated otherwise, ordinal numbers (e.g., first, second, third, etc.)are used to distinguish or identify different elements or steps in agroup of elements or steps, and do not supply a serial or numericallimitation on the elements or steps of the embodiments thereof. Forexample, “first,” “second,” and “third” elements or steps need notnecessarily appear in that order, and the embodiments thereof need notnecessarily be limited to three elements or steps. It should also beunderstood that, unless indicated otherwise, any labels such as “left,”“right,” “front,” “back,” “top,” “bottom,” “forward,” “reverse,”“clockwise,” “counter clockwise,” “up,” “down,” or other similar termssuch as “upper,” “lower,” “aft,” “fore,” “vertical,” “horizontal,”“proximal,” “distal,” “intermediate” and the like are used forconvenience and are not intended to imply, for example, any particularfixed location, orientation, or direction. Instead, such labels are usedto reflect, for example, relative location, orientation, or directions.It should also be understood that the singular forms of “a,” “an,” and“the” include plural references unless the context clearly dictatesotherwise.

FIG. 1A is a schematic illustration of a data storage device 100including a data storage medium and a head for reading data from and/orwriting data to the data storage medium. As shown in FIG. 1A, the datastorage device 100 includes a data storage medium or disc 102 and a head104. The head 104 including one or more transducer elements (not shownin FIG. 1A) is positioned above the data storage medium 102 to read datafrom and/or write data to the data storage medium 102. In the embodimentshown, the data storage medium 102 is a rotatable disc or other magneticstorage medium that includes a magnetic storage layer or layers. Forread and write operations, a spindle motor 106 (illustratedschematically) rotates the medium 102 as illustrated by arrow 107 and anactuator mechanism 110 positions the head 104 relative to data tracks onthe rotating medium 102. Both the spindle motor 106 and actuatormechanism 110 are connected to and operated through drive circuitry 112(schematically shown). The head 104 is coupled to the actuator mechanism110 through a suspension assembly which includes a load beam 120connected to an actuator arm 122 of the mechanism 110 for examplethrough a swage connection.

The one or more transducer elements of the head 104 are coupled to headcircuitry 132 through flex circuit 134 to encode and/or decode data.Although FIG. 1A illustrates a single load beam 120 coupled to theactuator mechanism 110, additional load beams 120 and heads 104 can becoupled to the actuator mechanism 110 to read data from or write data tomultiple discs of a disc stack. The actuator mechanism 110 isrotationally coupled to a frame or deck (not shown) through a bearing124 to rotate about axis 126. Rotation of the actuator mechanism 110moves the head 104 in a cross track direction as illustrated by arrow130.

FIG. 1B is a detailed illustration (side view) of the head 104 above themedium 102. The one or more transducer elements on the head 104 arefabricated on a slider 140 to form a transducer portion 142 of the head104. The transducer portion 142 shown includes write elementsencapsulated in an insulating structure to form a write assembly 144 ofthe head. As shown, the head 104 includes a bearing surface (forexample, and air bearing surface (ABS)) 146 along a bottom surface 150of the head or slider facing the medium 102. The head 104 is coupled tothe load beam 120 through a gimbal spring 151 coupled to a top surface152 of the head or slider 140 facing away from the medium 102. Themedium 102 can be a continuous storage medium, a discrete track medium,a bit patterned medium or other magnetic storage medium including one ormore magnetic recording layers.

During operation, rotation of the medium or disc 102 creates an air flowin direction 107 as shown in FIG. 1B along the air bearing surface 146of the slider 140 from a leading edge 154 to the trailing edge 156 ofthe slider 140 or head 104. Air flow along the air bearing surface 146creates a pressure profile to support the head 104 and slider 140 abovethe medium 102 for read and/or write operations. As shown, thetransducer portion 142 is formed at or near the trailing edge 156 of theslider 140. A transducer/head portion in accordance with one embodimentis described below in connection with FIGS. 2A and 2B.

FIGS. 2A and 2B depict ABS and side views, respectively, of aperpendicular magnetic recording (PMR) transducer 200. The PMRtransducer 200 may be a part of a merged head including the writetransducer 200 and a read transducer (not shown). Alternatively, themagnetic recording head may be a write head only including the writetransducer 200. The PMR transducer elements shown in FIGS. 2A and 2B areillustratively included in a recording head such as recording head 104of FIGS. 1A and 1B.

The write transducer 200 includes an under-layer/substrate 202, a mainpole 204, a trailing edge shield 206 and side shields 208. Theunder-layer 202 may include multiple structures which are under the pole204. In some embodiments, the multiple structures may include readsensor layers, read sensor shields, etc. In other embodiments, no readsensor structures may be included. The write transducer 200 may alsoinclude other components including but not limited to coils (denoted byreference numeral 210 in FIG. 2B) for energizing the main pole 204.

The main pole 204 resides over under-layer 202 and includes sidewalls212 and 214. Sidewalls 212 and 214 are separated from the side shields208 by non-magnetic side shield gaps (SSGs) 216. The top (trailing)surface of the main pole 204 also has a beveled portion 218. The bottom(leading) surface of the main pole 204 may also include a leadingsurface bevel 220. A Trailing edge shield gap (TSG) 222 is formedbetween the trailing edge shield 206 and the main pole 204.

FIGS. 2C and 2D depict air bearing surface and side views, respectively,of a perpendicular magnetic recording (PMR) transducer or head 250 thathas a wrap-around shield configuration in accordance with anotherembodiment. As can be seen in FIG. 2C, side shields 208 are connectedbelow a leading edge or bottom edge of the main pole 204. In otherrespects, heads 200 and 250 are substantially similar.

In write heads/transducers 200 and 250, the TSG 222 extends over oroutside the SSGs 216 in a cross-track direction, forming overhangs 224that separate the trailing edge shield 206 from portions of the sideshields 208. The overhangs 224 may be produced by a write headfabrication process that employs photo patterning to define a shape anddimensions of TSG 222 as part of the steps for its formation. Ingeneral, a recording head with a TSG including overhangs may havecertain on-track performance advantages, but may also produce side trackerasure (STE) and adjacent track interference (ATI) which may bedetrimental to a reliability of the recording head, particularly at highdata-writing rates.

Tests show that the erasure field is strongest along the side shield(SS)-TSG edge adjacent to the write pole. This erasure field is in-phasewith the writer pole field. Accordingly, any method to reduce this fieldwill help reduce erasure risks.

The side shields may also suffer from an intermittent reversed shieldcondition (e.g., a condition in which an original or set magnetizationdirection of the shields is switched). Under a reversed shieldcondition, erasure fields dramatically increase in the write head. Areduction of erasure fields by low activation of the side shields mayhelp check erasure fields generated from the reversed shield condition.

New generation writers are designed to achieve relatively high tracksper inch (TPI) and bits per inch (BPI). Reduction of the gaps betweenthe write pole and the side shields (e.g., SSG 216 reduction) mayachieve high TPI and BPI. However, this could result in a reduction ofthe write field due to an increase in leakage of flux from the writepole to the closely located shields. If the field loss is substantial,gradient loss might occur, which can hamper BPI capability.

To address the above erasure-related problems, embodiments of thedisclosure replace a top portion 226 of the side shield 208 along theoverhang region 224 with a thin layer of low saturation magnetization(B_(S)) material. As will be described in detail further below, in someembodiments, the low B_(S) SS cap layer may extend all the way up to aback of the side shield 208 in an x direction (e.g., a stripe heightdirection). In certain other embodiments, the low B_(S) SS cap layer maybe present only in a front portion of the side shield 208. In someembodiments, low B_(S) SS cap layer may not extend beyond overhangregion 224 in a y direction (e.g., a cross-track direction). In additionto addressing erasure-related problems, writer performance benefits arealso provided by such embodiments.

In some embodiments, a potential loss of field that may result fromrelatively small gaps between the write pole and the side shields may bemade up by removing a part of the shield material at the back of theside shield 208, thereby creating a step (not shown in FIGS. 2A-2D) inthe side shield 208 at its back. In some embodiments, the step featuremay not extend beyond overhang region 224 in the y direction (e.g., thecross-track direction). Embodiments including the low B_(S) SS cap layerin the side shield 208 are first described below in connection withFIGS. 3A-3E. Thereafter, embodiments including the step feature in theside shield are described in connection with FIGS. 5A-5J.

FIG. 3A shows a bearing surface view of a write head 300 that includes alow B_(S) SS cap layer in accordance with one embodiment. FIG. 3B is aninside view of the write head 300 showing the low B_(S) SS cap layerextending to a back portion of a main side shield layer. It should benoted that the write pole or main pole 204 is not shown in FIG. 3B inorder to depict the low B_(S) SS cap layer along an entire stripe heightof the side shield in the x direction.

Write head 300 of FIGS. 3A and 3B includes elements similar to thoseincluded in write head 200 of FIG. 2. Additionally, a trailing edgeshield seed layer 302 is shown over TSG 222 of write head 300. As can beseen in FIG. 3B, write head 300 includes side shields 308, with eachside shield 308 having a main SS layer 308A and a low B_(S) SS cap layer308B. In some embodiments, main SS layer 308A may have a B_(S) value ofabout 1.6 Tesla (T) and may be between about 20 nanometers (nm) andabout 50 nm thick. In certain embodiments, main SS later may be amulti-layered structure. In different embodiments, low B_(S) SS caplayer 308B may have a B_(S) value between about 0.5 T and 1.0 T and maybe between about 5 nm and about 30 nm thick. In the embodiment shown inFIG. 3B, low B_(S) SS cap layer 308B extends from bearing surface 146 toa back end 304 of the write head 300. As indicated above, in certainembodiments, low B_(S) SS cap layer 308B may not extend from the bearingsurface 146 to the rear end 304 of write head 300 and may extend onlypartially along a top surface 306 of side shield 308 in the x-direction(e.g., the stripe height direction). In the embodiment of FIG. 3A, thelow B_(S) SS cap layer 308B may not extend substantially beyond overhangregion 224 in the y direction (e.g., the cross-track direction).Further, in the embodiment shown in FIG. 3A, side shields 308 areseparate portions on either side of the write pole 204 and are notconnected together below the write pole. An insulating material 310(shown in FIG. 3A) is included between the separate shield portions 208.In alternate embodiments, the side shield portions 208 may be connectedbelow the write pole 204. Such embodiments of write heads are referredto herein as wrap-around writers. Examples of embodiments of wrap-aroundwriters are shown in FIGS. 3C, 5D and 3E.

FIG. 3C is a bearing surface view of a wrap-around write head 350 inaccordance with one embodiment. FIG. 3D is an inside view of the writehead 350 showing the low B_(S) SS cap layer extending to a back portionof a main side shield layer. In the interest of simplification, elementsof write head 350 other than trailing edge shield 206, TSG 222, sideshields 308 and write pole 204 are not shown in FIG. 3C. It should benoted that the write pole or main pole 204 is not shown in FIG. 3D inorder to depict the low B_(S) SS cap layer along an entire stripe heightof the side shield in the x direction.

As indicated above, a difference between wrap-around write head 350 andwrite head 300 (of FIGS. 3A and 3B) is that, instead of side shields 308being separated below write pole 204 as in write head 300 (of FIGS. 3Aand 3B), the side shields 308 of write head 350 are joined under writepole 204. In other respects, wrap-around write head 350 and split sideshield write head 300 (of FIGS. 3A and 3B) are substantially similar. Inthe embodiment of FIG. 3C, low B_(S) SS cap layer 308B is positionedbelow overhang region 224 in a manner described above in connection withFIGS. 3A and 3B. Further, in the embodiment shown in FIG. 3C, low B_(S)SS cap layer 308B may extend from the bearing surface 146 to a rear end304 of the write head 350 as shown in FIG. 3D. In certain embodiments,low B_(S) SS cap layer 308B may not extend from the bearing surface 146to the rear end 304 of write head 350 and may extend only partiallyalong a top surface 306 of side shield 308 in the x-direction (e.g., thestripe height direction). In the embodiment of FIG. 3C, the low B_(S) SScap layer 308B does not extend beyond overhang region 224 in the ydirection (e.g., the cross-track direction).

FIG. 3E is a bearing surface view of a wrap-around write head 375 inaccordance with another embodiment. Wrap-around write head 375 issubstantially similar to wrap-around write head 350 of FIGS. 3C and 3D.However, in wrap-around write head 375, low B_(S) SS cap layer 308Bincludes a vertical portion 376 that may extend to the trailing edgeshield (not shown in FIG. 3E) in a z direction (e.g., a down-trackdirection) and is positioned on a side 378 of overhang region 224. Inthe embodiment shown in FIG. 3E, low B_(S) SS cap layer 308B may extendfrom the bearing surface to a rear end (similar to 304 of FIG. 3D) ofthe write head 375. In certain embodiments, low B_(S) SS cap layer 308Bmay not extend from the bearing surface to the rear end of write head375.

FIG. 4 is a graph 400 that includes plots of results obtained from writeheads with and without a low B_(S) SS cap layer. Plot 402 is for abaseline write head (e.g., a write head that does not include a lowB_(S) SS cap layer). Plot 404 is for a write head (e.g., 300, 350, 375)that includes a low B_(S) SS cap layer. In FIG. 4, horizontal axis 406represents track number and vertical axis 408 represents normalizederasure fields. Track 0 is the track on which the write operation withthe write head takes place, and the track numbers on either side oftrack 0 denote tracks on either side of track 0. The recorded fields aremaximum at each track during the writer operation of switching betweenopposite polarities where the current driving the main pole is between1-4 GBPS (gigabits per second) frequency. A comparison of plots 402 and404 shows that the erasure fields from the design with the low B_(S) SSCap are less compared to the baseline design. A comparison of plots 402and 404 also shows that the low B_(S) SS Cap makes the fields on bothsides more symmetrical (as seen in plot 404). The region of the lowB_(S) (here 1.0 T) SS Cap receives considerable flux which leaks fromthe write pole close to its trailing edge. However, the low B_(S) capcannot generate the same amount of field as a 1.6 T material of the mainshield layer would have generated, driven by the leaking write poleflux. This means that the peaks in the erasure field would be cut out.

As noted above, writer side shields may also suffer from an intermittentreversed shield condition (e.g., a condition in which an original ormagnetization direction of the shields is switched). The change inmagnetization direction may result in magnetic stress being concentratedonto the SS-TSG edge region, which may manifest in higher erasurefields. One example of a side shield design that has a potential toalleviate symptoms from the reversed shield condition is described belowin connection with FIGS. 5A-5J.

FIGS. 5A and 5B are ABS and inside views, respectively, of a write headembodiment 500 that includes a back step feature 502 behind the bearingsurface 146 to help mitigate erasure fields generated from the reversedshield condition. It should be noted that the write pole or main pole204 is not shown in FIG. 5B in order to depict the back step feature 502within the side shield 308. The back step feature 502 may be formed byremoving a portion of main side shield layer 308A up to, for example,100-200 nm from the bearing surface 146 in the x direction orstripe-height direction. In some embodiments, the back step feature 502does not extend beyond overhang region 224 in the y direction (e.g., thecross-track direction) and therefore the back step feature 502 is hiddenin the view shown in FIG. 5A. Further, in the embodiment shown in FIGS.5A and 5B, the back step feature 502 extends from a rear end 504 oftrailing surface bevel 218 to the back end 304 of the write head 500 inthe x-direction (e.g., the stripe height direction). In someembodiments, the back step feature 502 may not extend all the way to theback end 304 of write head 500 in the x-direction (e.g., the stripeheight direction).

FIGS. 5C, 5D and 5E are ABS, inside and top-down views, respectively, ofa write head embodiment 550 that includes a back step feature 502 and alow B_(S) SS cap layer 308B. Other than including the low B_(S) SS caplayer 308B, write head 550 is substantially similar to write head 500 ofFIGS. 5A and 5B. In the embodiment shown in FIGS. 5C, 5D and 5E, lowB_(S) SS cap layer 308B extends from ABS 146 to rear end 504 of trailingsurface bevel 218 in the x-direction (e.g., the stripe heightdirection). However, in certain embodiments, the low B_(S) SS cap layer308B may also be included on back step feature 502. In such embodiments,the low B_(S) SS cap layer 308B would extend from the ABS 146 to backend 304 of the write head 550. In some embodiments, the low B_(S) SS caplayer 308B does not extend beyond overhang region 224 in the y direction(e.g., the cross-track direction).

FIGS. 5F and 5G are ABS and inside views, respectively, of a wrap-aroundwrite head embodiment 575 that includes a back step feature 502 behindthe bearing surface 146 to help mitigate erasure fields generated fromthe reversed shield condition. As indicated above, a difference betweenwrap-around write head 575 and write head 500 (of FIGS. 5A and 5B) isthat, instead of side shields 308 being separated below write pole 204as in write head 500 (of FIGS. 5A and 5B), the side shields 308 of writehead 575 are joined under write pole 204. In other respects, wrap-aroundwrite head 575 and split side shield write head 500 (of FIGS. 5A and 5B)are substantially similar. Therefore, interest of brevity, a descriptionof the similar elements is not repeated.

FIGS. 5H, 5I and 5J are ABS, inside and top-down views, respectively, ofa wrap-around write head embodiment 580 that includes a back stepfeature 502 and a low B_(S) SS cap layer 308B. Other than including awrap-around shield instead of a split side shield, write head 580 issubstantially similar to write head 550 of FIGS. FIGS. 5C, 5D and 5E,and therefore a description of the similar elements is not repeated.

Table 1 included below shows different write head parameters obtainedfrom simulations. Table 1 compares results of a baseline write headdesign (e.g., a write head without a low B_(S) SS Cap layer and withouta SS back step feature) and write head designs including one or more ofthe low B_(S) SS Cap layer and the SS back step feature. In Table 1below, different parameters are shown in percentage (%) over theperformance of the respective write heads of a baseline design.

TABLE 1 Write Maximum Down-track Field head effective field gradientangle Curvature design [%] [%] [%] [%] Baseline 0 0 0 0 Back 0.82 4.261.58 −7.58 step Back 1.29 5.14 1.92 −6.44 step + low B_(S) SS CapFrom Table 1, it is seen that there is a gain in field/writability anddown-track gradient or error rate over a baseline write head design. Thegains are even higher when there is a low B_(S) SS Cap layer.

FIG. 6 is a graph 600 that include plots of results obtained from writehead designs with and without at least one of a low B_(S) SS Cap layerand a SS back step feature. Plot 602 is for a baseline write head (e.g.,a write head without a low B_(S) SS Cap layer and without a SS back stepfeature). Plot 604 is for a write head (e.g., 500, 575) that includes aSS back step feature and no low B_(S) SS Cap layer. Plot 606 is for awrite head (e.g., 550, 580) that includes a SS back step feature and alow B_(S) SS Cap layer. In FIG. 6, horizontal axis 406 represents tracknumber and vertical axis 608 represents erasure field in T. Track 0 isthe track on which the write operations with the write heads take place,and the track numbers on either side of track 0 denote tracks on eitherside of track 0. In FIG. 6, the plots 602, 604, 606 are an average ofthe peak fields sensed by the side tracks. As can be seen in FIG. 6,erasure fields rise for the back step SS design (e.g., write head 500,575) compared to the baseline design, especially between side tracks of2-4 on both sides of the center track (e.g., track 0). A large amount offlux is dumped into the step part of the SS causing the erasure fieldsto flare up, as part of the SS is removed at the back. When the lowB_(S) SS Cap is included (e.g., write head 550, 580), the erasure fieldis reduced by the physical process described above (e.g., by restrictingfields emanating from the low B_(S) material during operation of thewrite head).

FIGS. 7 and 8A-8J illustrate steps carried out during manufacturing of awrite head such as 300 of FIGS. 3A and 3B. FIG. 7 is a flow diagram 700of an example process sequence to form a capped side shield in amagnetic recording head such as 300. It should be noted that, whilethere are several approaches to forming a magnetic recording head with acapped SS, the method of FIG. 7 is an example of a process that givesconsideration for control of tolerances of key elements of the recordinghead design. It should also be noted that, although the processdescribed below in connection with FIGS. 7 and 8A-8J is for capped sideshield formation in a split side shield write head, similar processsteps may be taken with a wrap-around shield design for these features.

The process sequence intercepts the recording head build after sideshields adjacent to a write pole (WP) have been planarised as shown inFIG. 8A. FIG. 8A illustrates a first partial write head structure 800that includes a variety of materials that comprise the planar surface.The materials/layers include magnetic side shield layers 802, sideshield seed layers 803, non-magnetic write gap layers 804 and aprotective non-magnetic write pole cap layer 806. The write pole layeris denoted by reference numeral 808.

Starting with first partial write head structure 800, steps 702-706 offlowchart 700 of FIG. 7 are performed. Step 702 involves depositing aninductively coupled plasma (ICP) stop later 810. This is followed bydepositing a chemical-mechanical planarization or polishing (CMP) stoplayer 812 at step 704. Then, at step 706, an ICP hardmask layer 814 isdeposited. The performance of steps 702-706 provides a second partialwrite head structure 816 shown in FIG. 8B.

On second partial write head structure 816, photoresist etch windows arepatterned adjacent to each side of the write pole 808 in accordance withstep 708, and layers 814 and 812 are etched by a first etching processin accordance with step 710. This includes shaping the ICP hardmask 814and CMP stop 812 using fluorine based chemistry or any of a range ofalternative chemistries. The first etching process is stopped on the ICPstop layer 810 in accordance with step 712. Chemistry is then switched,and the process proceeds to step 714 where the ICP stop layer 810 andthe magnetic side shield layers 802 are etched using a patternedhardmask for a fixed time to achieve a nominal side shield etch depth,which is denoted by reference numeral 818 in FIG. 8C. This results in athird partial write head structure 820 of FIG. 8C. Structure 820 iscleaned in accordance with step 716 to remove any unwanted by-product,thereby preparing the wafer surface for liftoff deposition of a SS caplayer (e.g., a 1.0 T material layer) having lower magnetic flux carryingcapacity than the magnetic side shield layers 802.

Process steps 718-722 of FIG. 7 are then performed on the third partialwrite head structure 820. At step 718, liftoff deposition of a thin lowB_(S) (e.g., 1.0 T) material layer is carried out. At step 720, CMP iscarried out to bring the thin low B_(S) material layer to a level of CMPstop layer 812. At step 722, CMP stop layer 812 is removed by anysuitable process. Performance of steps 718-722 creates an infill of thelow B_(S) material (denoted by reference numeral 822) having a surfacewhich is planar with the non-magnetic cap 806 on write pole 808, andprovides a fourth partial write head structure 824 is shown in FIG. 8D.

At step 724, a first material removal process is carried out to reduce aheight of the write pole layer 808 at the ABS. The first materialremoval proves results in the upper surface of the write pole beingmoved to a lower position shown by dashed line 826 in FIG. 8E, whichshows a fifth partial write head structure 828.

Sidewalls of the write pole 808 are tapered and a write pole widthdecreases with reduction in write pole height due the tapered nature ofthe writer pole 808. In a plane orthogonal to the ABS, a sloped profileis induced in the write pole at step 724. Tapering the write pole inthis plane serves to increase a magnetic flux density at the ABS, whichimproves writeablity performance. Better writeability boosts the arealdensity capability of a data storage device such as a disc drive.Completion of step 724 provides a sixth partial write head structure 830shown in FIG. 8F. Sixth partial write head structure 830 includes a newsurface 832 where the write pole height is smaller than any referencepoint behind the ABS. A sectional view showing surface 832 is providedin FIG. 8G.

On sixth partial write head structure 630, to control a write fieldgradient, a shaped gap (e.g., a TSG) at the top or trailing edge of thewrite pole 808 on the ABS plane is fabricated. This is achieved byperforming steps 726 and 728 in method 700 of FIG. 7. At step 726, across-track non-magnetic gap layer 834 is deposited to provide a seventhpartial write head structure 836, which is shown in FIG. 8H. At step728, a cross-track gap or TSG formation process is carried out to definecross-track widths of the TSG and the low B_(S) SS cap layer portions822 at the ABS. The non-magnetic gap layer 834 is shaped using aphotoresist mask, and ion beam etching (IBE), for example, is performedto achieve a trailing edge gap (e.g., TSG) of nominal width 837 shown inFIG. 8I, which illustrates an eighth partial write head structure 838.An over-etch is applied during formation of non-magnetic gap layer 834to remove portions of the low B_(S) SS cap layer 822 of on top of sideshield layers 802. This process results in confining a width of the lowB_(S) SS cap layer 822 not to exceed the width of the non-magnetic gaplayer 834.

Finally, steps 730 and 732 of method 700 are performed on eighth partialwrite head structure 838 to fabricate a trailing edge shield or trailingedge shield. At step 730, a trailing edge shield seed layer 840 isdeposited on the top surface of structure 838. This is followed bypatterning and plating magnetic trailing edge shield material 842 shownin FIG. 8J. Removal of photoresist, backfilling with alumina, and CMPare carried out to achieve a planar trailing edge shield surface or topsurface of structure 844 of FIG. 8J.

The write head formation process described above in connection withFIGS. 7 and 8A through 8J and can also produce the back step design inFIGS. 5C-5E. The cap recess from the ABS can be achieved by performingall steps in the process shown in FIG. 7 with one small modification.The modification involves recessing the photomask used on theperformance of step 708 to a desired design point, which may be one of arange of possible values. Also, it should be noted that a processsimilar to that described above in connection with FIGS. 7 and 8Athrough 8J may be used to form write heads of the type shown in FIGS. 3Dand 3E. Further, the write heads of the type shown in FIGS. 3D and 3Emay also be fabricated with a back step feature in some embodiments.

The illustrations of the embodiments described herein are intended toprovide a general understanding of the structure of the variousembodiments. The illustrations are not intended to serve as a completedescription of all of the elements and features of apparatus and systemsthat utilize the structures or methods described herein. Many otherembodiments may be apparent to those of skill in the art upon reviewingthe disclosure. Other embodiments may be utilized and derived from thedisclosure, such that structural and logical substitutions and changesmay be made without departing from the scope of the disclosure.Additionally, the illustrations are merely representational and may notbe drawn to scale. Certain proportions within the illustrations may beexaggerated, while other proportions may be reduced. Accordingly, thedisclosure and the figures are to be regarded as illustrative ratherthan restrictive.

One or more embodiments of the disclosure may be referred to herein,individually and/or collectively, by the term “invention” merely forconvenience and without intending to limit the scope of this applicationto any particular invention or inventive concept. Moreover, althoughspecific embodiments have been illustrated and described herein, itshould be appreciated that any subsequent arrangement designed toachieve the same or similar purpose may be substituted for the specificembodiments shown. This disclosure is intended to cover any and allsubsequent adaptations or variations of various embodiments.Combinations of the above embodiments, and other embodiments notspecifically described herein, will be apparent to those of skill in theart upon reviewing the description.

The Abstract of the Disclosure is provided to comply with 37 C.F.R. §1.72(b) and is submitted with the understanding that it will not be usedto interpret or limit the scope or meaning of the claims. In addition,in the foregoing Detailed Description, various features may be groupedtogether or described in a single embodiment for the purpose ofstreamlining the disclosure. This disclosure is not to be interpreted asreflecting an intention that the claimed embodiments require morefeatures than are expressly recited in each claim. Rather, as thefollowing claims reflect, inventive subject matter may be directed toless than all of the features of any of the disclosed embodiments.

The above-disclosed subject matter is to be considered illustrative, andnot restrictive, and the appended claims are intended to cover all suchmodifications, enhancements, and other embodiments, which fall withinthe true spirit and scope of the present disclosure. Thus, to themaximum extent allowed by law, the scope of the present disclosure is tobe determined by the broadest permissible interpretation of thefollowing claims and their equivalents, and shall not be restricted orlimited by the foregoing detailed description.

What is claimed is:
 1. A write head comprising: a bearing surface; awrite pole having a front surface that forms a portion of the bearingsurface; a trailing edge shield above the write pole; a trailing edgeshield gap layer between the trailing edge shield and the write pole; abi-layered side shield for the write pole, the bi-layered side shield ispositioned below the trailing edge shield and comprises a main sideshield layer having a trailing surface bevel and a low saturationmagnetization cap layer on the trailing surface bevel, the lowsaturation magnetization layer having a front surface that forms aportion of the bearing surface, the low saturation magnetization caplayer comprises a substantially horizontal portion at the bearingsurface that is positioned below the trailing edge shield gap layer andis in contact with the trailing edge shield gap layer.
 2. The write headof claim 1 and wherein the bi-layered side shield comprises a firstbi-layered side shield portion on a first side of the write pole and asecond bi-layered side shield portion on a second side of the writepole, and wherein the first bi-layered side shield portion is separatedfrom the second bi-layered side shield portion below the write pole. 3.The write head of claim 1 and wherein the bi-layered side shieldcomprises a first bi-layered side shield portion on a first side of thewrite pole and a second bi-layered side shield portion on a second sideof the write pole, and wherein the first bi-layered side shield portionis connected to the second bi-layered side shield portion below thewrite pole.
 4. The write head of claim 1 and wherein the low saturationmagnetization cap layer comprises a substantially vertical portion thatis positioned on a side of the trailing edge shield gap layer and is incontact with the trailing edge shield gap layer.
 5. The write head ofclaim 1 and wherein the bi-layered side shield comprises the main sideshield layer that includes a portion that is below the low saturationmagnetization cap layer, wherein the main side shield layer has a stripeheight extending from the bearing surface to a back of the write head ina direction perpendicular to the bearing surface.
 6. The write head ofclaim 5 and wherein the low saturation magnetization cap layer has astripe height that is less than or equal to the stripe height of themain side shield layer.
 7. The write head of claim 5 and furthercomprising a back step feature in an upper portion of the main sideshield layer of the bi-layered side shield, wherein the back stepfeature is recessed behind the bearing surface.
 8. The write head ofclaim 7 and wherein a surface of the back step feature is without thelow saturation magnetization cap layer.
 9. The write head of claim 7 andwherein a surface of the back step feature comprises the low saturationmagnetization cap layer.
 10. The write head of claim 7 and wherein themain side shield layer of the bi-layered side shield comprises a lowerportion that is below the back step feature.
 11. An apparatuscomprising: a bearing surface; a write pole having a front surface thatforms a portion of the bearing surface; and a side shield for the writepole, the side shield comprising: a low saturation magnetization caplayer having a front surface that forms a portion of the bearingsurface; and a main side shield layer having a back step featurerecessed behind the bearing surface and a trailing surface bevel onwhich the low saturation magnetization cap layer is disposed, the mainside shield layer having a saturation magnetization that is higher thana saturation magnetization value of the low saturation magnetization caplayer, and a width of the back step feature is substantially equal to awidth of the low saturation magnetization cap layer.
 12. The apparatusof claim 11 and wherein a width of the main side shield layer at thebearing surface is greater than the width of the low saturationmagnetization cap layer at the bearing surface.
 13. The apparatus ofclaim 11 and further comprising a trailing edge shield gap layer overthe write pole and over the low saturation magnetization cap layer. 14.The apparatus of claim 11 and wherein the side shield comprises a firstportion on a first side of the write pole and a second portion on asecond side of the write pole, and wherein the first portion isseparated from the second portion below the write pole.
 15. Theapparatus of claim 11 and wherein the side shield comprises a firstportion on a first side of the write pole and a second portion on asecond side of the write pole, and wherein the first portion isconnected to the second portion below the write pole.
 16. The apparatusof claim 11 and wherein a portion of the main side shield layer is belowthe back step feature.
 17. A write head comprising: a bearing surface; awrite pole having a front surface that forms a portion of the bearingsurface; a trailing edge shield above the write pole; a trailing edgeshield gap layer between the trailing edge shield and the write pole;and a bi-layered side shield for the write pole, the bi-layered sideshield is positioned below the trailing edge shield and comprises a caplayer and a main side shield layer, below the cap layer, having a backstep feature in an upper portion of the main side shield layer, with alower portion of the main side shield layer having an upper surface thatcomprises a bottom surface of the back step feature, the back stepfeature being recessed behind the bearing surface and having a widththat is substantially equal to a width of the cap layer.
 18. The writehead of claim 17 and wherein the cap layer comprises a low saturationmagnetization cap layer over the main side shield layer.